Seam for paper cans



' June 11, 1929. w. R. LENDERKING SEAM FOR PAPER CANS F iled March 10, 1927 amnion 1 Patented June 11, 1929.

UNITED STATES WILLIAM R. LENDERKING, OF BALTIMORE, MARYLAND.

SEAN FOR PAPER CANS.

Application filed March 10, 1927. Serial No. 174,332.

My invention relates to cylindrical paper cans and relates particularly to the seam by which the end disc forming the bottom or top end of the can is secured to the cylindrical body portion of the can body or slip cover.

Cylindrical paper cans are extensively used and it is common to secure the end discs to the cylindrical body portion of the can body or slip cover by a crimping operation involving folding the end of the body portion over a flange on the end disc and so forming the parts together as to form a more or less tight joint without the use of paraffin or other sealing material. \Vhile it has not been found diflicult to unite the parts by the crimping operation closely enough to permit use of the can for dry materials, it has been found difficult to so unite the parts as to make a joint which will be liquid tight and will remain liquid tight for any considerable length of time after the can has been filled with material which is wholly or partly liquid.

It is the object of my present invention to provide an improved seam for cylindrical paper cans by which the end discs may be secured to the cylindrical body portions by crimping so as to secure a joint which will be more highly resistant to liquid than those now in use and will be practically liquid tight.

\Vith the objects above indicated and other objects hereinafter explained in View my invention consists in the construction and combination of elements hereinafter described and claimed.

Referring to the drawings Figure 1 is a central, vertical, sectional view of a paper can having the bottom secured to the body and the top secured to the body portion of the slip cover by the scam of my present invention.

Figure 2 is a detail, vertical, sectional view showing the parts assembled preparatory to the crimping operation.

Figure 3 is a view similar to Figure 2 but showing the completed seam, and

Figure 4 is a View similar to Figures 2 and 3 but showing a modification.

In the drawings 1 indicates the cylindrical body member of the paper can or vessel and 2 indicates the cylindrical body member of the slip cover. The lower or outer portion of the body member 1 is offset at 3 so as to form between it and the main portion of the body member a shoulder 4. The end member consists of a disc 5 having near its periphery an inwardly extending groove (3, having an inner wall 7 and an outer wall 8. The outer wall 8 is cylindrical and its outer face is in contact throughout its extent with the inner face of the offset 3. The outer wall 8 extends outward in cylindrical form from the outer edge of the inner wall 7 at an acute angle 9, the angle being as acute as it can be made without breaking the paper stock from which the end disc is cut and formed. The diameter of the outer face of the cylindrical outer wall 8 is slightly greater than the interior diameter of the main portion of the body member 2, so that when inserted in place ready for the crimping operation its base rests against shoulder 4.

When the end disc is thus in position the outer end of the offset portion 3 is curled over the outer end of the outer wall 8 of the groove forced against the inner face of this outer wall 8 of the groove, thus enclosing this outer wall 8 and holding its base firmly against the shoulder 4.

By continuing further the crimping operation, applying more pressure to the crimping tool, the end disc being supported on a suitable mandrel, the end of the ofi'set portion 3 may be forced towards the disc 5 so as to cause the outer end of the outer wall 8 of the groove 6 to be rolled over inward and to force the end of the offset portion 3 into the groove 6 as shown at 10 in Figure 4, and still further pressure will force its end against the base of the outer wall 8 and to fold upon itself to form the outwardly extending rib 11, as shown in Figure 4.

Having thus described my invention, what I claim is In an end seam for cylindrical paper vessels the combination of a body member having its end portion offset outward so as to form an annular shoulder and an end disc having an inwardly extending annular groove near-its edge, having its outer wall at substantially a right angle to its central portion and extending outward as a cylin-. der beyond the plane of the body of the disc said groove having its inner wall extending from the base of the outer wall towards the centre of the disc at an acute angle, the base of the outer wall of the disc tween the inner and outer walls of the restin upon the shoulder of the bed memgroove and to hold said outer wall of the her t e end ortion outside the s oulder groove in engagement with the annular 10 being crim e over the outer wall of the groove in the body member.

5 groove, wit its end extending into the In testimony whereof, I hereunto aflix my groove and bearing against the outer wall signature. of the groove at its base to form a lock be- WILLIAM R. LENDERKING. 

